(19)
(11) EP 0 467 358 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
13.01.1993 Bulletin 1993/02

(43) Date of publication A2:
22.01.1992 Bulletin 1992/04

(21) Application number: 91112021.0

(22) Date of filing: 18.07.1991
(51) International Patent Classification (IPC)5: H04B 10/14, H04L 27/22
(84) Designated Contracting States:
DE FR GB

(30) Priority: 18.07.1990 JP 187997/90

(71) Applicant: FUJITSU LIMITED
Kawasaki-shi, Kanagawa 211 (JP)

(72) Inventors:
  • Naito, Takao
    Kawasaki-shi, Kanagawa, 211 (JP)
  • Chikama, Terumi
    Machida-shi, Tokyo 194 (JP)
  • Watanabe, Shigeki
    Kawasaki-shi, Kanagawa, 216 (JP)
  • Kiyonaga, Tetsuya
    Kawasaki-shi, Kanagawa 211 (JP)
  • Nakamoto, Hiroshi
    Kawasaki-shi, Kanagawa 216 (JP)
  • Ishikawa, George
    Yokohama-shi, Kanagawa 223 (JP)

(74) Representative: Lehn, Werner, Dipl.-Ing. et al
Hoffmann, Eitle & Partner, Patentanwälte, Postfach 81 04 20
81904 München
81904 München (DE)


(56) References cited: : 
   
       


    (54) A demodulator and a polarization diversity receiver for coherent optical communication provided with the demodulator


    (57) A demodulator comprising an OR/NOR circuit (1), an exclusive OR/NOR circuit (3), and a delay circuit (2) is disclosed as that capable of being suitably formed into a monolithic IC. Also, a polarization diversity receiver for coherent optical communication using the above demodulator as its constituent is disclosed as that having a smaller number of variable gain amplifiers and accordingly having the controlling circuit made simpler in structure.






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